The ubiquity of wireless devices and the finite radio spectrum present a disparity between the availability of, and demand for, wireless access. New technologies should be able to efficiently use the spectrum of transmission frequencies and/or operate as non-interfering secondary users in existing spectrum. Personal area networks include examples of such technologies and usually exhibit modest bitrates and short ranges. However, a need exists for communications systems that can operate over various areas or ranges, including larger areas or ranges, and which address the foregoing and other problems in the art.